Why? Who care what the numbers are. We aren't going to get to impressive number with all the mods for the 3IS right now anyways. It's a preference of sound or look we are going for. Want great dyno numbers with some mods? Wrong car.

 

Who cares? I care.

"It's a preference of sound or look we are going for." No, it is a preference of sound or look YOU are going for.

Sorry but we have different ideas. Life is good.

Aloha,
Larry

 

Race much?

 

It would be interesting to see a comparison of stock vs. intake/exhaust mods just to see how much torque is lost with the mods. I understand that folks do these mods primarily for a different look and sound, but at what cost to performance and drivability? Here you go. ------> Butt Dyno

 

torque cannot be lost by opening up exhaust and intake...the torque curve is shifted right, higher peak at higher RPM.

 

Any in-cabin drone with muffler delete?
i am debating between trying a muffler mod and muffler delete.

 

delete it you will love the sound

 

wow...okay...i may like it, but is there DRONE?

 

so i finally went ahead and deleted the mufflers and added dual tips but took on a different innovative approach just to learn.
my goal was to increase the volume of exhaust at high RPM, i like the more exotic high pitched sound (have a Cammed chevy V8 for the low tone note) and absolutely NO DRONE when cruising on HWY since this is my daily, and change the tips to one of a kind on IS....well not so much anymore since the new RC F have something similar......so to reduce the drone effect and have the higher pitched sound (low notes belong on bigger displacement v8s in my opinion) i decided to replace the muffler with a straight pipe 1/4" diameter smaller than stock 2" for the following reasons:
create a resistance analogous to stock muffler,
reduce droning (since drone is caused by larger pipes slowing moving air and lower frequency resonance) by going to a smaller tail pipe section (which increases the exit velocity of exhaust)....plus as the further the exhaust travels along the pipe the more it cools down which also means it shrinks in volume (the further you are from the engine the less influence the exhaust has on performance, hence larger diameter catbacks only gain you 5 HP)....smaller pipe keeps the air velocity speed up....particularly i saw a number of systems where Headers have larger diameter going into smaller section near muffler to keep the scavanging velocity....so here it is:

 

boring stock pic:



bye bye stock muffler, i originally wanted to cut open the stock muffler, but the shop said its a waste of time and money as this muffler is small and chambered, standard restriction:

 

now it was time to add the straight pipes and tips.

the stock header is about 2.5" or more going down to 2.25" near the cats and resonators and down to 2" to the muffler....so irelaced the muffler with a 1.75" pipe for reasons stated above

 

here is the final product, dual tip.
will capture some video with gopro hero 3 for you, but NO highway drone, fun city driving, and more high pitched to match F sport intake (i drilled a hole in the intake...a la F sport) which complements this exhaust nicely...or vice versa.

 

you can go smaller diameter at tailpipe as exhaust gasses slow and cool by the time they reach the muffler...smaller diameter can increase the velocity of the cooled higher density exhaust gas

http://www.pontiacstreetperformance..../exhaust3.html

http://www.pontiacstreetperformance..../exhaust2.html

http://www.go.jeep-xj.info/HowtoExhuast.htm

 

you will love the sound, not a lot of in cabin drone at all for me

 

i agree...i was soooo worried about the drone, but the sound is great
its actually sounds like a raspy porsche..i like it and matches nice with f sport exhaust
i got Double Wall Exhaust Tips and aero turbine small resonators just in case

going down 1/4 in piping probably helped with sound as well.

i will post pics once i get vids from my iphone......POS iphone makes it a pita to upload to youtube